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S5 Spectral Line Cataloguing

S5 Spectral Line Cataloguing. Keith Thorne for the Spectral Line Working Group. Why Look at Spectral Lines?. Direct impact on GW searches Broad peaks cut into bandwidth (Pulsar) Narrow L1/H1 coherences (Pulsar) Broad H1/H2 coherences (Stochastic)

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S5 Spectral Line Cataloguing

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  1. S5 Spectral Line Cataloguing Keith Thorne for the Spectral Line Working Group March 2007 LIGO/Virgo Meeting - DetChar

  2. Why Look at Spectral Lines? • Direct impact on GW searches • Broad peaks cut into bandwidth (Pulsar) • Narrow L1/H1 coherences (Pulsar) • Broad H1/H2 coherences (Stochastic) • Non-stationarity in line sources causes transients (Burst) • They complicate data-conditioning filters (Burst) • Indicate unwanted couplings into GW channel • Specific sources typically are at particular frequencies • Can be used to monitor interferometer elements • Drumhead, body modes used to track test mass temperature March 2007 LIGO/Virgo Meeting - DetChar

  3. Spectral Line Measurement • Control Room Investigations • Fourier, Spectral Coherence Tools (Schofield) • DMT Monitors - LineMon (Klimenko), SixtyHertzMon (Riles) • Offline Studies • Daily Spectral Line-Finding Summary (KT) • Can also do special runs on any other channels • SFT-based Spectrograms (Dupuis) • Environmental Coherence Catalogue (Carleton College) • Results from Search Groups • Narrow Lines seen in Pulsar Group analyses (Mendel, Riles) • Broader Coherences seen in Stochastic Group analyses • PEM - DARM_ERR coherences (Mandic, Fotopoulos) March 2007 LIGO/Virgo Meeting - DetChar

  4. Daily Line-Finding Pipeline • Running since November 2005 • Makes daily summaries of DARM_ERR spectral lines • Reports on changes in lines prepared about every ~3 weeks March 2007 LIGO/Virgo Meeting - DetChar

  5. High-Frequency Line Search • Extended to 8192Hz for Butterfly, Drumhead modes • Supplanted by monitor of high-rate GW channel to track internal modes (to measure test mass temperature) March 2007 LIGO/Virgo Meeting - DetChar

  6. S5 H1/L1 Spectral Lines • Pulsar searches are particularly concerned with lines that are coherent between the 4K detectors (H1, L1) • Short Fourier Transforms (SFTs) were searched with Fscan and spectrograms prepared (Mendell, Dupuis) • Required f of 2.2 x10-4 (generous Doppler window), SNR > 4 • Found 3-Hz sidebands on 60Hz, 16Hz harmonics • Also coherences from violin modes, Duotone(?) near 1920Hz • Quasi-stationary lines coincident within 10 mHz between H1 and L1 reported from PowerFlux (Riles) • Strongest were harmonics of 16 Hz • These were used to focus later studies (to address issues most of need by pulsar group) March 2007 LIGO/Virgo Meeting - DetChar

  7. S5 Coherence Spectrograms March 2007 LIGO/Virgo Meeting - DetChar

  8. S5 H1-H2 Coherences • Prepared by Stochastic Group • Robert Schofield attempted feature identification (Sept 06) March 2007 LIGO/Virgo Meeting - DetChar

  9. January 2007 Commissioning • Power supply ripple monitor installed to search for line sources (Schofield) • Fscan spectrograms prepared for ripple data (Mendel) • Long-mysterious 546, 564, 566, 646, 648Hz lines seen in +-15V center supply ripple! • Mitigation attempt on 10Hz comb from IRIG-B • 3-Hz sidebands of 60Hz tracked down to the Neslab PSL chiller (SCR pulsed heaters) • 280Hz lines from power supply fans in 4K PSL • Broad, wandering lines in spectrograms mitigated by improved cooling of H1 LSC racks March 2007 LIGO/Virgo Meeting - DetChar

  10. Environmental Coherence Catalogue • Work done by Carleton College (Nelson Christensen, et.al.) • Monthly analysis of coherence between GW channel and selected environmental channels • 1024 s periods, 0.977 mHz resolution • Peaks identified as exceeding cutoff level at 3 sigma • Also “mining” the same results for specific lines from the S5 pulsar searches • Results for August, September 2006 ready • Web page: http://virgo.physics.carleton.edu/Hans/coherence/peaks/index.html March 2007 LIGO/Virgo Meeting - DetChar

  11. Sample pulsar line coherences • H1 - 66 Hz - Coherence with LVEA, BSC1 EM channels • L1 - 90.475Hz - Coherence with BSC1 accelerometers • L1 - 127.285Hz - Coherence with coil magnetometers March 2007 LIGO/Virgo Meeting - DetChar

  12. “Eternal” Spectral Line Mysteries • 329 Hz Lines (all IFOs) • Strong enough that 2nd, 3rd harmonics seen • Speculation that they are Beam Splitter (BS) Violin Modes • 335 Hz Lines (H1, etc.) • Rung up very strongly when beam power raised prior to science mode • Speculation that they are Recycling Mirror (RM) violin modes • 646-648 Hz Lines (all IFOs) • 2nd, 3rd Harmonics often seen • Coherences in other interferometer channels (+/-15V power supply ripple?) • 546,566 Hz Lines (H1 only) • Again, 2nd, 3rd harmonics often seen • Coherent with some WFS channels (+/-15V power supply ripple?) • 2.60, 2.64 Hz combs (H2 only) • Extend from 40-100 Hz • Seen in ETMX, ETMY shadow sensors March 2007 LIGO/Virgo Meeting - DetChar

  13. Possible Future Work • Improve follow-up on commissioning investigations • Continue Environmental Coherence Catalog • Help Pulsar, Stochastic Groups prepare final lists • Perhaps plan commissioning work to mitigate 546, 646Hz lines apparently due to +-15V power supplies • Perhaps more commissioning investigations at Livingston • Do we need more planning of our activities (or not?) • Work on joint investigations with Virgo • Suggestions from the floor… March 2007 LIGO/Virgo Meeting - DetChar

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